Combination container and dry pet food for increased shelf life, freshness, palatability, and nutritional value

ABSTRACT

The combination of a substantially gas impermeable container and a dry pet food of high soluble fiber content that has a water activity within the range of 0.5 to 0.8. The result is long lasting, highly nutritious dog food that can be substantially free of added preservatives, antimycotics, and other unnatural chemicals.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation of Ser. No. 08/912,410, filed on Aug.18, 1997.

FIELD OF THE INVENTION

This invention relates generally to a package or container and dry petfood combination that does not require preservatives or removal ofoxygen from the bag and particularly to the resulting increased shelflife, freshness, palatability, and nutritional value of the dry pet foodin combination with the container.

BACKGROUND OF THE INVENTION

Companion pets, such as dogs and cats, are important family members andmay live to be 15, 20 or even more years contributing to the well beingand mental health of the family. These companion animals longevity willbest be served through good nutrition, therefore, it is important toprotect the nutritional content, digestibility, and palatability of thecompanion pet food.

Pet foods are now generally classified into three types by their watercontent, namely: dry pet foods which generally have a water content ofless than about 15% by weight, more particularly within the range ofapproximately 6-12%; semi-moist pet foods which generally have a watercontent of 20-40% by weight; and pet foods which have a high watercontent of more than 45% by weight, more particularly in the range ofabout 65-85%.

Pet foods having a high water content are generally sold in canned form.These canned pet foods require retorting because the high content ofwater is suitable for growth of microorganisms. Moreover, after canopening, the canned food should be stored in a refrigerated statebecause they undergo spoilage very soon. Thus the pet foods of highwater content in canned form require high cost for processing incanning, and are inconvenient to store. The dry pet foods and thesemi-moist pet foods are easier to package and transport, and need notbe refrigerated after they are opened. They are easy to give animals,and are convenient to pet keepers.

The products of semi-moist content are unstable unless they containextensive additives, some of which may be harmful to the animal. Due totheir higher level of moisture content, they are more susceptible tomicroorganism growth than dry pet foods. Microorganisms which may causespoilage are living in the products of semi-moist content because theirwater content is not so low as to inhibit growth of microorganisms andthe temperature for heat treatment of these products is not so high asto achieve complete sterilization. Even if the products areheat-sterilized completely, they are susceptible to secondarycontamination because they are packed in a simplified form. The productsof semi-moist content, therefore will spoil soon if no measure is taken.The most prevalent practice of preventing microbial growth is to addsome form of preservatives and/or antimycotics.

The dry pet foods contain up to about 15% moisture by weight and are thesimplest to handle and store and least expensive to ship. Hard, dry petfood, while being easy to store and handle, is not as palatable as theother classes of pet food for some animals. Thus, although dry pet foodmay be very nutritional, in some cases it is not a particularlyacceptable pet food to either the pet or the pet owner. This lowerpalatability is due partly to the deterioration of the pet food oroverdrying of the pet food in an effort to prevent deterioration.

Two major causes of deterioration in dry pet food are microbial growthand oxidation. Both of these deterioration factors cause decreased dietpalatability and decreased nutritional value. In addition, microbialgrowth also increases the risk of food intolerance. Some microorganismsand the toxins they produce may cause vomiting, diarrhea, and even deathof animals consuming them. Problems associated with pet food oxidationalso include decreased immune function and therefore increasedsusceptibility to infectious diseases. Cardiovascular diseases, musculardystrophy, or degeneration and steatitis, any of which may result indeath, also occur as a result of the ingestion of oxidized or rancidfood. Although oxidation of commercial pet food severe enough to causethese effects is uncommon, sufficient oxidation to result in decreaseddiet palatability and a dry lusterless hair coat is quite common.

Methods commonly used to minimize these effects is to dry the foodsufficiently to prevent microbial growth and to add preservatives to thefood. Too much drying of the food however makes it hard and crumblyreducing the foods palatability to pets. Further, the heat used to drythe food increases oxidation and, if the heat is sufficient, it alsodecreases the diet's digestibility. Preservatives used are primarilyanti-oxidants, although substances such as sugars and propylene glycolhave been added to bind water making it unavailable either for microbialgrowth or oxidation. The major anti-oxidants used are mixed tocopherols,various acids, and synthetic chemicals such as BHA, BHT, and mostcommonly ethoxyquin. Ethoxyquin, which is used as an antioxidant inrubber products, is well recognized as one of the most efficientantioxidants available. Although it is allowed in pet foods, it is notallowed in foods intended for people and many question its safety forpets. A 3.5 years, two consecutive generations, study of beagle dogsshowed that liver pigmentation changes and elevated liver enzymes werefound in dose-dependent levels following ingestion of ethoxyquin. PetFood Industry, 38(3):51-53, (May/June 1996). While the study concludedthat the liver pigmentation was not considered critically significantand the dog's overall health did not appear to be affected, analternative to such additives would be preferred. Whether true or not,many pet owners believe that these chemicals, particularly ethoxyquin,are harmful to their pets.

In addition to the problems associated with anti-oxidants, the largeamount of sugar and/or sugar alcohols sometimes added, reaching as largeas 20-35% by weight, is too high for usual feeds of animals and isdetrimental to nutritional balance. Moreover, a high sugar contentcauses poor digestion in certain animals, especially old animals.Further, propylene glycol used as an antiseptic could have potentiallyadverse affects on the health of an animal after long term feeding ofpet foods containing large amounts of propylene glycol. Accordingly,none of these measures are entirely satisfactory because of the problemsof nutritional balance, the health of the animals, and palatability.Further, attempts to solve these problems have heretofore resulted inwide variations in the storagability of pet foods.

Regardless of the procedures taken to prevent dry pet fooddeterioration, those currently used are inadequate. In a recent study,Dr. Jim Corbin, University of Illinois, reported that "of 37 variouscommercial pet foods from store shelves, 43% had peroxide values inexcess of 20 meq/kg of fat". Pet Food Industry, 38(1)6,(January-February 1996). Animal fat rancidity odor is easily detectedby, and food palatability decreased for people at peroxidated values of20 meq/kg or greater. Since a dog's sense of smell is 50-100 times moresensitive the people's, a much lower value is undoubtedly detected bythem, decreasing the diet's palatability. This degree of oxidation alsodecreases the nutritional value of required essential or unsaturatedfatty acids, which if sufficiently severe results in their deficiencyaffects. This is first indicated by a dry lusterless hair coat, a commonproblem in dogs receiving dry commercial dog food.

To prevent these effects, vacuum packaging in gas impermeable bags hasrecently been used. Although this method quite likely is effective, noresults currently have been published or made available. In addition,vacuum packaging of pet foods has several major disadvantages include:costly equipment, a rate of production too slow for most manufacturingplants, and a rough poorly readable package unacceptable to manyretailers and pet owners. Of three companies that have so far triedvacuum packaging, one has stopped using it and the other two have goneout of business.

Two things, water and oxygen, are necessary for microbial growth in andoxidation of a food. The present invention inhibits microbial growth andoxidation of pet food through minimizing both the water and oxygenavailable for food spoilage to occur. This decrease in available waterand oxygen is accomplished without the use of chemical preservatives orvacuum packaging, thus eliminating the problems associated with them asmentioned above.

In addition, the present invention will provide numerous health benefitsover prior art container and dry pet food combinations. In addition, thepresent invention provides maintained freshness and palatability as wellas nutritional value of the pet food. Finally, the present inventionpermits prolonged shelf life and decreased production, storage andtransportation costs.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a combination container anddry pet food that inhibits microbial growth and oxidation without theuse of vacuum packaging or addition of chemical preservatives.

Another objective of the invention is to provide a combination containerand dry pet food with maintained freshness, improved palatability, andmaintained nutritional value.

It is a further object of the invention to provide a combinationcontainer and dry pet food with prolonged shelf life.

Yet another objective of the invention is to provide a combinationcontainer and dry pet food that results in decreased production,storage, and transportation costs.

Additional objectives and advantages of the invention will be set forthin part in the description that follows, and in part will be obviousfrom the description, or may be learned by the practice of theinvention. The objects and advantages of the invention will be obtainedby means of the instrumentalities and combinations particularly pointedout in the appended claims. To achieve the objects and in accordancewith the purpose of the invention, as embodied and broadly describedherein, the present invention provides a combination container and drypet food with increased shelf life, freshness, palatability, andnutritional value.

Ingredients high in soluble fibers such as oats, flax seed meal andpsyllium, were selected and used to produce a diet high in solublefiber. This is the preferred natural dog food for this invention. Thesefiber ingredients were used instead of the corn, wheat or animalingredients which are commonly used in the pet food industry but containlittle soluble fiber. Soluble fiber confers many health benefitsincluding: assisting in the normalization of intestinal transit;prevention of diarrhea, constipation, or excessive hard stools; adecrease in blood cholesterol, therefore, preventing cardiovasculardisease; binding of pathogens in the intestinal track, thereforereducing their effect; and a decrease in post prandial hyperglycemia. Inaddition to these numerous health benefits, soluble fiber also binds30-70 times their weight of water rendering the water unavailable frommicrobial growth and for oxidation. The amount of edible soluble fibermaterial present in the pet food is preferably above 3% by weight andmost preferably within the range of 5% to 15% by weight.

In another embodiment, the invention comprises a combination containerand dry pet food wherein the container is gas impermeable, thereforefurther minimizing oxidation without the need for removing oxygen fromthe bag either by vacuum, nitrogen fill or oxygen scavengers.

Yet another embodiment of the invention comprises a combinationcontainer and dry pet food that results in prolonged shelf life due tothe minimized oxidation and reduced bacterial growth and decreasedproduction storage and transportation costs. These reductions in costare due to the ability to produce a greater quantity of pet food in asingle run, no additional cost necessary to nitrogen fill or provideoxygen scavengers in the container to remove oxygen, and no specialtemperature or humidity requirements. This longer shelf life furtherresults in the ability for a shopkeeper to order more pet food per orderthereby decreasing the cost of shipping per unit.

The method and package used to achieve these objectives as well asothers will become apparent from the following detailed description ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the presently referredembodiments of the invention, which together with the followingexamples, serve to explain the principles of the invention and thesynergy of the combination.

The invention relates to a combination container and dry pet food. Itprovides a means for storing dry pet food with maintained freshness,palatability, and nutritional value, as well as prolonged shelf life. Inaddition, the invention relates to a combination container and dry petfood that allows for decreased production, storage, and transportationcosts.

In an effort to provide to the pet food industry a pet food that is bothpalatable and easy to store, and with a reasonable shelf life, the petfood industry has focused much effort in the area of preserving thedifferent moisture classes of pet food. See for example, Friedman etal., U.S. Pat. No. 4,495,208 issued Jan. 22, 1985; Ueno et al., U.S.Pat. No. 4,444,796 issued Apr. 24, 1984; Bone et al., U.S. Pat. No.4,273,788 issued Jun. 16, 1981; Ernst et al., U.S. Pat. No. 4,158,706issued Jun. 19, 1979; and Bernotavicz, U.S. Pat. No. 3,985,904 issuedOct. 12, 1976, all of which are incorporated herein by reference.Broadly speaking, these prior art pet food compositions used acombination of high heat treatment and the addition of preservativesand/or antimycotics. In addition, these products frequently haveincluded a high level of sugars, edible organic acids and inorganicacids to maintain pH. Finally, the packaging of these pet food productsincludes reduction of available oxygen through vacuum packaging,nitrogen fill, or oxygen scavengers. Thus the package is costly as isthe process and food quality, especially its natural state, issacrificed with preservatives, flavor masks, etc.

In the present invention, the water and oxygen necessary for microbialgrowth in and oxidation of food are minimized through the use of solublefiber and a container constructed of gas impermeable materials.

One way to reduce the water available for microbial growth and foroxidation is to bind the water. In the present invention, soluble fiberis used which binds water in the range of about 30-70 times the weightof the soluble fiber. The amount of water available, or unbound, isindicated by a food or substance's water activity. As shown in Table 1 awater activity of 0.64 or less insures the absence of microbial growthand at 0.4 to 0.5 oxidation rate is the slowest. In the presentinvention, this water activity is kept at a range of about 0.5 to about0.8 and preferably 0.7 or below, and a percent moisture by weight of petfood at about 6% to 10%.

                                                    TABLE 1                   

    ______________________________________                                        Water Activity (W.A.) and its Effects                                                   W.A.                                                                              Effects                                                         ______________________________________                                         1.0      100% of water is unbound or available                                 0.90      90% of water is unbound or available                                <0.90   most microorganisms can't grow because of                                     inadequate water available                                            0.80      oxidation rate is 120% above minimum                                0.70      oxidation rate is 70% above minimum                                 0.64      lowest W.A. at which any organisms can grow and                              therefore below which is optimum to ensure their                             absence                                                               0.60      oxidation rate is 25% above minimum                                 0.40-0.50 oxidation rate is slowest                                           0.30      oxidation rate is 16% above minimum                                 0.20      oxidation rate is 45% above minimum                                 0.10      oxidation rate is 110% above minimum                              ______________________________________                                    

In one embodiment of the present invention, the pet food is comprised ofingredients consisting of flax seed meal, lentils, oat groates, peas,sunflower seed oil, canola seed meal, rice, dehydrated cane juice,yeast, sea kelp, calcium carbonate, salt, psyllium and spirulina (listedin order of decreasing amount in the diet). The dry pet food alsocontains 20% crude protein, 15% crude fat, 8% moisture, 5% crude fiberand 5% ash. This results in a pet food that is several times higher thanmost pet foods in unsaturated fatty acids which are susceptible tooxidation and in soluble fiber to bind water to reduce microbialactivity and oxidation.

In the present invention, the gas impermeable container in which the drypet food is stored, minimizes the available oxygen without resorting tovacuum packaging or oxygen scavengers. There are several oxygen barriermaterials available that can be used in the creation of a gasimpermeable container. See for example, Anderson, U.S. Pat. No.5,500,303 issued Mar. 19, 1996, incorporated herein by reference. Asurprising result was that neither use of preservatives nor removingoxygen from the bag either by vacuum, nitrogen flush or oxygenscavengers is necessary when the food composition described is sealed ina gas impermeable bag as described. Virtually no oxidation occurs duringstorage, thus, with this invention shelf life of pet food can beprolonged and freshness, palatability, and nutritional value maintained.

A film barrier package according to one embodiment of the invention hasan inner ply of a polymeric material, an outer ply of a polymericmaterial, and a substantially air free space disposed therebetween. Eachof the two plies is formed of a sheet of polymeric material; these twoplies may be formed of the same or different polymers. Their individualoxygen transmission rates should be approximately equal.

In some applications, the two plies may be formed by simply folding asingle sheet of polymeric material to provide two plies adjacent oneanother and joined together along one edge thereof. In such a design,the inner and outer plies of the barrier may be sealed together, such asby heat sealing or the like, to fully define the anaerobic spacetherebetween--the space should not be open to the atmosphere.

The plies may be formed of any known polymer having sufficient barrierproperties for use in packaging applications. Films currently used inthe art include those made from polyester, polypropylene, PVDC, nylon,and polyethylene, as well as multi-layer laminate films formed ofcontiguous, bonded layers of these and other polymers. Any of thesefilms may be advantageously used in the present invention. One of thegoals of the invention, though, is to provide a particularly costeffective oxygen barrier for use in packaging applications. In order tofurther that end, in many situations it will be advantageous to use acheaper polymeric film.

The thickness of these two plies of polymeric material may be varied asdesired. It is contemplated that the thickness of each of these plieswill be dependent on the particular application for which the barrierpackage of the invention is being used. This thickness may also dependupon the composition of the plies because, as explained above, theoxygen transmittance of a polymeric film will depend to a very largeextent upon the material from which it is formed.

The present invention results not only in improved pet health and foodacceptance, but in decreased production, storage, and transportationcosts. Due to the high soluble fiber content and lower moisture level agreater quantity of pet food can be created per production run resultingin lower production costs. In addition, since the pet food can be placeddirectly into the container without the need for nitrogen flush, oxygenscavengers or vacuum sealing the production costs are also reduced.Storage and transportation costs are also reduced because there are nospecial temperature or humidity requirements. Transportation costs arealso reduced because the containers of pet food have a longer shelf lifewhich means larger quantities can be purchased per shipment thusreducing the shipping price per pound.

The combination of pet foods of the present invention free ofadulterating preservatives, anti-oxidants, anti-mycotics, flavor agentsand masking agents and moisturizer additives, and the barrier packageproduce a synergistic result never achieved before in the pet foodindustry. No all-natural, storable dog food has ever been developed thatwas as animal healthful without having to use canned storage orexpensive oxygen free vacuum or inert gas packaging. As a result of thisinvention natural, healthy choice dog foods can be made which have longshelf life and avoid expensive, time-consuming packaging, heretoforeused. As a result, unnatural, perhaps non-healthy food modificationspreviously used to escape package deficiencies can now be avoided.

It is to be understood that the application of the teachings of thepresent invention to a specific problem or environment will be withinthe capabilities of one having ordinary skill in the art in light of theteachings contained herein. The examples of the products and processesof the present invention appear in the following examples which are tobe taken as illustrative but not limiting.

EXAMPLE 1 Water Activity and Oxidation Study

A study was conducted to determine the optimum amount of naturalpreservative, if any, the optimum type of packaging material, and theoptimum atmosphere within the container to insure maintained freshness,nutritional value, palatability and shelf life.

To prevent microbial growth and oxidation without the use of chemicalpreservatives, the following natural preservatives were put into thediet and evaluated:

(1) no preservatives (none);

(2) 0.5% (500 ppm) Naturox (Kemin Industries, Des Moines) which consistsof mixed tocopherols, rosemary extract, citric acid and mono- anddi-glycerides (N);

(3) 1% lauracedin, 5% lactic acid and 0.5% Naturox (1LLN); and

(4) 3% lauracedin, 5% lactic acid and 0.5% Naturox (3LLN). Lauracedin isa fatty acid shown to prevent microbial growth and whose activity isenhanced by the presence of lactic acid.

Four different types of packaging were considered in this studyincluding two paper bags (AP and UC) that are routinely used in the petfood industry. The four bags consist of:

1. A 6 mil paper, 1 mil polyethylene bag, freely gas permeable (AP bag);

2. A 6 mil paper, 2 mil polyethylene bag, freely gas permeable (UC bag);

3. A moderately gas impermeable 48 gauge PET barrier bag with an oxygentransmission rate of 0.586 cc/100 sq inches/24 hours/atm (L bag); and

4. A gas impermeable foil bag with an oxygen transmission rate of lessthan 0.01 cc/l00 square inches/24 hours/atm and with a one way valvethat lets air out but not in (K bag).

The atmosphere in each of the bags was further modified by doing one ofthe following:

1. Nothing (Neither);

2. Nitrogen flush to reduce oxygen to below 2% before sealing the bag (NFlush);

3. Oxygen scavenger packet put into the bag before sealing it (O Scav);or

4. Both nitrogen flush and oxygen scavenger before sealing the bag(Both).

The food tested in the study was an organic ingredient containing adultdog diet consisting of flax seed meal, lentils, oat groates, peas,sunflower seed oil, canola seed meal, rice, dehydrated cane juice,yeast, sea kelp, calcium carbonate, salt, psyllium, and spirulina(listed in order of decreasing amount in the diet). It contained 20%crude protein, 15% crude fat, 8% moisture, 5% crude fiber and 5% ash.

Two samples of each of the preceding combination of factors(preservatives, packaging and atmosphere), which consisted of 112samples, were used in the study. Each sample was evaluated for theamount of oxidation present by thiobarbituric acid (TBA) analysis oneweek after it was produced and packaged and again 4 months later. Duringthis 4-month period the samples were stored at 37° C. and 85% relativehumidity to induce the amount of oxidation that would occur during 12months storage at room temperature and ambient humidity. The TBAanalysis measures the concentration of malonaldehyde produced as aresult of oxidation. Its concentration correlates best with theoxidation induced decrease in diet palatability, which is the firsteffect of food oxidation. Because of this, it is considered to be thebest indication of shelf life stability. Following one year storageeffects accelerated to 4 months, water activity was also measured as anindication of the diets susceptibility to microbial growth.

As shown in Tables 2, 3 and 4 the diet studied contained sufficientsoluble fiber and other constituents to bind adequate water so thatregardless of the preservatives, atmosphere or bags used, its wateractivity was sufficiently low to prevent microbial growth (<0.64) andwas near that at which oxidation is minimized (0.4-0.5).

                  TABLE 2                                                         ______________________________________                                           Preservatives Effect on Water Activity on Pet Food From Gas                   Impermeable Bags Without An Altered Atmosphere                                   Preservatives                                                                           3LLN    1LLN     N    None                                    ______________________________________                                        Water Activity                                                                            0.57    0.57       0.56 0.57                                      ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                            Atmosphere Effect on Water Activity of Pet Food Containing                           Naturox From Gas Impermeable Bags                                      Preservatives                                                                             N Flush O Scav   Both Neither                                 ______________________________________                                        Water Activity                                                                            0.51    0.60       0.58 0.56                                      ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                           Bag Effect on Water Activity of Pet Food Containing Naturox                      With Nitrogen Flush and Oxygen Scavenger                                       Bag:     UC      AP      L     K                                       ______________________________________                                        O Perm. cc/si/d                                                                           Freely  Freely    0.00585                                                                             <0.0001                                     Water Activity 0.66 0.58 0.65 0.56                                          ______________________________________                                    

As shown in Table 5 the amount of oxidation occurring in the food wasdirectly related to the oxygen or gas permeability of the bag containingit. During the 12 month simulated study, the food in the freelypermeable paper bags became highly oxidized, whereas no significantoxidation occurred in most gas impermeable bags.

                  TABLE 5                                                         ______________________________________                                                Bag Effect on Oxidation of Pet Foods as Indicated by                    Malonaldehyde (mg/kg) Formed in 4 months at 37° C.  & 85% RH              Bag:        UC      PF      L     K                                      ______________________________________                                        O Perm. cc/si/d                                                                            Freely  Freely    0.00586                                                                             <0.0001                                    M. aldehyde-mg/kg 6.1        5.3 0.6 0.1                                    ______________________________________                                    

As shown in Tables 6 and 7, none of the preservatives or alteredatmospheres decreased oxidation. In gas permeable bags (UC & AP)oxidation was high whereas no oxidation occurred in food in the gasimpermeable bags (K), whether it contained a preservative or not (Table6). Altering the atmosphere in gas impermeable bags (K) isn't needed asno oxidation occurs regardless of the atmosphere. However, in moderatelygas impermeable bags (L) when neither oxygen scavengers or nitrogenflush were used some oxidation occurred, which was prevented wheneither, or both, were used. (Table 7).

                  TABLE 6                                                         ______________________________________                                          Preservative Effect on Oxidation of Pet Food as Indicated by                       Malonaldehyde (mg/kg) Formed in 4 months at 37° C. and 85%      RH                                                                                        O Perm-  Naturox Lauracedin &                                                                           No Pre-                                   Bag              cc/si/d   only       Lactate  servatives                   ______________________________________                                        UC      Freely   8.1       7.09     3.9                                         AP               Freely    6.5       5.8        4.2                           L                0.00586   1.7       1.0        1.0                           K                <0.0001 -0.1      -0.1       0.0                           ______________________________________                                    

                  TABLE 7                                                         ______________________________________                                             Atmosphere Effect on Oxidation of Pet Food as Indicated by                  Malonaldehyde (mg/kg) Formed in 4 months at 37° C. and 85% RH                O Perm-   Oxygen                                                                                                Bag   cc/si/d      Scav.                                                     Nitrogen Flush Both   Neither       ______________________________________                                        UC   Freely    6.0      6.2       6.3   6.0                                     AP    Freely       5.3     5.7            5.3    5.0                          L     0.00586      0.6     0.8            -0.2   1.3                          K     <0.0001      -0.1    -0.1           -0.2   0.2                        ______________________________________                                    

As shown in Table 8, there is inadequate unbound water in the pet foodstudied to allow any microbial growth to occur, and little or nooxidation occurred even without the use of preservatives, nitrogenflush, oxygen scavengers or vacuum packaging when the food was packagedin gas impermeable bags. Oxidation during the 12 month accelerated studywas 2-times higher in moderately gas impermeable bags and 24 to 27-timeshigher in the freely gas permeable bags currently in common use in thepet food industry.

                      TABLE 8                                                 

    ______________________________________                                        Stability of Pet Food High in Soluble                                           Fiber Without Preservatives, Nitrogen Flush,                                               Oxygen Scavengers or Vacuum Packaging                            Bag           UC        AP  L     K     Optimum                             ______________________________________                                        Ox. Perm-cc/si/d                                                                          Freely  Freely  0.00586                                                                             <0.0001                                                                             0                                       Water Activity          0.66     0.58    0.65     0.56      0.6-0.4         Oxidation as indicated by malonaldehyde concentration (mg/kg of diet)              1 wk after 0.83    0.92  1.01  0.74  0                                                                              production                           After 4 mo. storage*     5.45 5.06 1.34 0.91 0                                During Storage          4.62     4.14    0.33     0.17      0               ______________________________________                                             *at 37° C.  and 85% RH which simulates the amount of oxidation     that would    occur in 12 months at room temperature and humidity.       

EXAMPLE 2 Palatability Study

The effects of the methods used for pet food preservation on foodpalatability is of critical importance. Studies comparing palatabilityof dog food with preservatives (as described in Example 1) compared todog food without preservatives were conducted. None of the preservativestested effected diet palatability. Food containing no preservatives waspreferred only 1.4 to 1 over the same dog food containing 0.5 Naturox,3% lauracedin and 5% lactic acid. However, as shown in Table 9, bags hada profound effect on palatability. Table 9 contains the results of a twopan preference study conducted to determine the palatability of the samefood put into different bags. The results are reported as the ratio ofthe mean percent that each of the two diets offered contribute to thetotal amount eaten by each of ten dogs at either 1 or 2 days feeding.For example, if dog 1 eats 30% diet A and 70% diet B, and dog 2 eats 10%diet A and 90% diet B, the mean is (10%+30%) divided by 2 dogs=20% dietA eaten, and 80% diet B eaten, for a preference ratio of B preferredover A by 80% to 20% or by 4 to 1. A preference ratio of less than 3 to1 is not considered significant, i.e. indicates little or no differencein palatability between the two diets. The effect of the different typesof bags on dry dog food palatability was determined in this study usingboth a dry extruded vegetarian dog food and a dry extruded poultry mealbased dog food. Both types of dog food contained 0.5% Naturox. Theatmosphere was not altered in any of the bags. As shown below, both thevegetarian dog food and the poultry meal based dog food from either ofthe two different types of gas impermeable bags were greatly preferredover the same diet from paper bags, whether the paper bags were polylined or unlined. The difference occurred even though there was nodifference in the amount of oxidation of the food in the gas impermeablebags from that in the paper bags.

The results in Table 9 show that, whether the dog food used wasvegetarian based or poultry meal based, the dogs clearly preferred dogfood contained in gas impermeable bags over that of dog food containedin paper bags (regardless of whether the paper bags were poly lined orunlined).

                                      TABLE 9                                     __________________________________________________________________________                             Effects of Bags on Pet Food Palatability                      {Gas Imperm-                                                                         {preferred over                                                                            by {Preference                                     Pet Food}        in  eable bags}    same diet in} {Paper Bag} a Ratio                                       of}                                           __________________________________________________________________________     Vegetarian                                                                            F              polylined                                                                             17 to 1                                         Vegetarian          K                             poly lined       123                                      to 1                                            Poultry meal   F                             poly lined       10.5 to 1       Poultry meal       F                             unlined          12.8                                      to 1                                          __________________________________________________________________________                  K =  gas impermeable foil bag (Kaypac)                           F = gas impermeable foil sandwiched between a layer of nylon and plastic      (FresCo).                                                                

In light of Example 1 and Example 2, it is clear that the pet food witha high soluble fiber content and a lower water activity when containedin a gas impermeable bag demonstrates markedly increased shelf life,freshness, and palatability.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described specifically herein. Suchequivalents are intended to be encompassed by the scope of the followingclaims.

What is claimed is:
 1. A substantially gas impermeable container havingat least two walls capable of forming an airtight seal that forms asubstantially airtight space defined by the walls devoid of oxygenscavengers nitrogen fill, or vacuum conditions, and containing withinthe substantially airtight space a dry pet food having a moisture levelin the approximate range of 5% to 15% by weight, soluble fiber contentof greater than 3% by weight, and having a water activity within therange of 0.5 to 0.8 caused substantially by the soluble fiber content.2. The container of claim 1 wherein the walls oxygen transmission rateis about 0.6 cc/100 sq. inches/24 hours/atm or less.
 3. The container ofclaim 1 wherein the walls oxygen transmission rate is in a range ofabout 0.6-0.01 cc/100 sq. inch/24 hours/atm.
 4. The container of claim 1wherein the walls are of a composition that includes a polymer, plastic,aluminum foil, metal, or polymer/metal composite.
 5. The composition ofclaim 4 wherein the polymer is selected from the group consisting of:polyvinylidene chloride, polyester, polypropylene, nylon andpolyethylene.
 6. The container of claim 1 further comprising a one-wayvalve that allows air to escape the sealed container but not enter thesealed container.
 7. The dry pet food of claim 1 wherein the wateractivity is 0.7 or less.
 8. The dry pet food of claim 1 wherein thesoluble fiber content is above 3%.
 9. The dry pet food of claim 1including ingredients selected from the group consisting of: flax seedmeal, lentils, oat groats, peas, sunflower seed oil, canola seed meal,rice, dehydrated cane juice, yeast, sea kelp, calcium carbonate, salt,psyllium and spirulina.
 10. The dry pet food of claim 1 furthercomprising about 20% crude protein, about 15% crude fat, about 8%moisture, 5% crude fiber and 5% ash.
 11. In combination, a dry pet foodof a moisture level in the appropriate range of 5% to 15% by weightincluding an amount of natural edible fiber containing material so thatsoluble fiber content is about 3% to about 15% by weight which causes awater activity within the range of 0.5 to 0.8, and a surrounding andsealing gas impermeable barrier package devoid of oxygen scavengers,nitrogen fill or vacuum conditions.
 12. The package combination of claim11 which uses multiple layer construction of bonded film materials. 13.The package combination of claim 11 wherein the gas impermeable barrierpackage is a film and foil composite.
 14. The container of claim 1wherein the soluble fiber content is in the range of 5% to 12% byweight.
 15. The method of decreasing deterioration of dry dog foodcomprising:decreasing water activity to 0.8 or less by including in thedry dog food natural edible soluble fiber containing materials sosoluble fiber content is greater than 3% by weight; packaging the foodin a substantially gas impermeable package devoid of oxygen scavengers,nitrogen fill or vacuum conditions.
 16. The method of claim 15 whereinthe step of minimizing water activity comprises including a greater than3% by weight natural edible soluble fiber in the pet food.
 17. Themethod of claim 15 wherein the step of minimizing oxidation comprisesplacing the pet food in a substantially gas impermeable barrier package.18. The method of claim 15 wherein the step of minimizing oxidation rateby controlling water activity.
 19. The method of claim 15 wherein thestep of minimizing oxidation comprises controlling water activity. 20.Dry pet food made by the process comprising:creating a dry pet foodhaving a moisture level between 5% and 15% by weight, and including anatural edible soluble fiber material so that soluble fiber content isgreater than 3% by weight; placing the food into a surrounding andsealing gas impermeable barrier package devoid of oxygen scavengers,nitrogen filler, and vacuum conditions, so that water activity is 0.8 orless caused substantially by the natural edible soluble fiber materialand oxidation is minimized because of the binding of water to thesoluble fiber material and limitation on entry of oxygen into thepackage.